基于近似熵的VDR人声识别技术研究

利用话者识别原理和语音数字信号处理技术对人声建模方法进行研究,建立了基于GMM模型的VDR环境下的人声识别基准系统;从分析影响人声识别率因素的角度出发,指出传统算法的不足,并提出一种基于近似熵的语音端点检测算法。理论分析和实验结果证明:新算法能有效屏蔽大动态冲击性噪声,解决了语音的虚检现象,并且在低信噪比0 dB情况下的识别率提升66%。     

Experimental Analysis of Variable Collective-pitch Rotor Systems for Multirotor Helicopter Applications

This paper presents an experimental study of variable collective-pitch rotor systems for multirotor helicopter applications. An experimental research facility has been established to conduct this research. The facility enables the high-resolution measurement of forces and torques produced by rotor systems. The power consumption of the rotor system during experimentation can also be recorded. The experimental research facility also allows for the characterisation of the effect of rotor systems on multirotor helicopter performance. It is shown that the variable collective-pitch rotors have a significant performance advantage over fixed-pitch rotors when comparing thrust response, and multirotor helicopter step input response performance. Further, it is observed that variable collective-pitch rotors are more efficient in terms of energy consumption than comparable fixed-pitch rotors under similar operating conditions.     

Global output‐feedback stabilization for high‐order nonlinear systems with unknown growth rate

This paper considers the global stabilization via time‐varying output‐feedback for a class of high‐order uncertain nonlinear systems with rather weak assumptions. Essentially different from the existing literature, the systems under investigation simultaneously have more serious nonlinearities, unknowns, immeasurableness, and time‐variations, which are indicated from the unknown time‐varying control coefficients and the higher‐order and lower‐order unmeasured states dependent growth with the rate of unknown function of time and output. Recognizing that adaptive technique is quite hard to apply, a time‐varying design scheme is proposed by combining time‐varying approach, certainty equivalence principle and homogeneous domination approach. One key point in the design scheme is the selection of the design functions of time, in order to compensate/capture the serious unknowns and serious time‐variations, and another one is the design of a time‐varying observer to rebuild the unmeasured system states. With the appropriate choice of the involved design functions, the designed controller makes all the signals of the closed‐loop system globally bounded and ultimately converge to zero. Copyright © 2016 John Wiley & Sons, Ltd.     

智能家居的“春天”来了

论述了智能家居的概念,着重阐述了智能家居及其核心技术的国内外发展历程,理清了智能家居的发展脉络。随后从技术、生产厂家、市场规模、消费者意识等方面论证了智能家居的“春天”已经来临。最后,对智能家居的未来发展进行了展望。     

BPEL 流程建模中的交叠模式分析与转换

由图形化流程建模语言生成可执行的业务流程语言(business process execution language,简称BPEL)时,对于源模型中顺序与并发结构交织的情况(称为交叠模式),传统的复制相关活动方法缺少系统分析及形式化描述.针对这一现状,提出基于工作流网的UML活动图生成BPEL方法,以自由选择工作流网作为活动图的理论基础,利用活的、有界的自由选择网系统的合成规则,定义合理的自由选择工作流网中的两种交叠模式,针对其中一种给出复制相关活动的形式化转换方法,并借助Petri网的并发正则表达式证明转换等价性,说明另一种交叠模式中复制相关活动方法的适用范围.针对BPEL流程建模及图形化流程语言生成块状语言过程中的交叠模式转换问题,给出形式化的描述与解决方法.     

DSP系统中PWM通道实现D/A转换精度的分析方法

以PWM作为D/A的功能接口,分析了不同电路对转换精度的影响,提出了以PWM接口输出经滤波电路获得的精度与电路结构及参数之间关系的分析方法,初步确定了理论上分析转换精度的步骤与方法.并以TMS320F2812为例对其PWM通道实现D/A转换扩展功能的精度做了实例计算,验证了理论分析的可行性与准确性.为磁悬浮数字控制系统的设计与预知其设计精度之间的关联提供了理论基础,可以为相关设计提供借鉴与参考.     

多描述编码与网络编码在无线传感器网络中的应用

多描述编码可以有效地防止图像数据的丢失,防止对单份数据的依赖,保证接收端收到图像的质量。网络编码可以有效提高网络带宽利用率。为了适应数据在无线传感器网络中的可靠传输,并节省网络的带宽,提出将多描述编码与网络编码相结合的思想,以多条路径传输为基础,将其应用在无线传感器网络中。     

中草药生态信息管理系统的分析与设计

以Visual Studio．net为开发平台,SQL Server2000为后台数据库进行设计与开发,实现对中草药资源信息进行数据分析和监测预警。系统不但可改进传统的管理方法,而且还可提高种植专业化水平,并为中草药资源可持续发展提供决策依据。     

Unpacking the effect of IT capability on the performance of export-focused SMEs: a report from China

Abstract.  Export-focused small and medium-sized enterprises (SMEs) in China face a number of barriers to success, two primary ones being the liability of foreignness and resource scarcity. In order to transcend these challenges and be able to survive/prosper in the hypercompetitive international market, where players include large resourceful multinational organizations with experience in varied national contexts, these firms need to develop different organizational capabilities. In this paper, we specifically examine the role of a key organizational capability – information technology (IT) capability – and its different dimensions, in determining performance of export-focused SMEs in China. Our study reveals that IT capability has a positive impact on such firms' performance. This finding indicates the need for their owners/managers to invest in IT capability. Further, the study also highlights specific sub-dimensions of IT capability that export-focused Chinese SMEs should (or should not) develop, so as to derive maximum performance-related gains for the minimum amount spent on IT.     

Stream segregation algorithm for pattern matching in polyphonic music databases

As music can be represented symbolically, most of the existing methods extend some string matching algorithms to retrieve musical patterns in a music database. However, not all retrieved patterns are perceptually significant because some of them are, in fact, inaudible. Music is perceived in groupings of musical notes called streams. The process of grouping musical notes into streams is called stream segregation. Stream-crossing musical patterns are perceptually insignificant and should be pruned from the retrieval results. This can be done if all musical notes in a music database are segregated into streams and musical patterns are retrieved from the streams. Findings in auditory psychology are utilized in this paper, in which stream segregation is modelled as a clustering process and an adapted single-link clustering algorithm is proposed. Supported by experiments on real music data, streams are identified by the proposed algorithm with considerable accuracy.